This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is a double-blind, randomized, multicenter but placebo controlled crossover study of a novel formulation of pancreatic enzyme for treatment of patients with cystic fibrosis and pancreatic insufficiency. The study proposes to treat a total of 26 patients at various centers including 5 patients here at the Penn State Hershey Medical Center. The primary study objective is to compare efficacy of this novel formulation to placebo in promoting fat absorption in these patients. There are various other secondary objectives including nitrogen absorption and safety and tolerability. After registration patients will be randomized to either begin with the study drug or begin with placebo, but in each case after initiating treatment with one or the other, patients will be crossed over to the opposite preparation. The GCRC is thus necessary for compliance with the study including six days of stool collection. At the end of the six days of study treatment, the patients will be switched to a "wash out period" of 3 to 14 days of their usual pancreatic enzyme supplementation, and then begin a second period with the opposite preparation (i.e., placebo or study drug). This second preparation will again be performed in the GCRC over a five to six day period.